Improvement in blast, smelting, and cupola furnaces



UNITED STATES :PATENT FFIGE.

SILAS C. SALISBURY, OF NEW YORK, N. Y.

IMPROVEMENT |N BLAST, SMLTING, AND cuPoLA FuRNAcEs.

Specification fomning part of Letters Patent No. 88,083, dated March 23, 1869.

To all whom it may concern:

Be it known that I, SILAs C. SALIsBURY, of

the city of New York, in the county of NewV York and State of New York, have invented certain new and useful Improvements in Blast, Smelting, and. Cupola Furnaces; and I do hereby declare that the following is a full, clear, and exact description thereof and of their mode or manner of operation, reference being had to the accompanying drawings, and to the letters of reference marked thereon, and making a part of this specification.

The object of my invention is to dispense, in blast and similar furnaces, with the usual means or apparatus employed for heating the airforthe hot-blast, and at the saine time secure a hot-blast of a much higher temperature than is usually obtainable, and thusV greatly increase and intensify the heat of the hot-blast, and thereby reduce the quantity of coal required to smelt iron or other ores. Y This I accomplish by a peculiar construction of the lower part of the furnace, whereby I make the furnace itself the means of heating the airblast supplied to it, and heating such blast also to a higher degree of heat than has been heretofore possible.

Figure l is a general perspective view of a furnace constructed according to my invention. Fig. 2 is a vertical section from front to rear, the interior chamber shown in perspective. Fig. 3 is a vertical section of Fig. l through w The present mode of preparing and supplying the hot-air blast used in blast and similar furnaces is by the use of two or more separate furnaces, generally placed at some distance from the main furnace, in which is placed a series of pipes, which is kept at a red heat, and into and through which cold air is forced by powerful engines and heated by passing through such pipes, and then, after being so heated, is forced through the tuyeres down to the bottom' of the furnace. Such blast is generally supplied under a pressure of from three to five pounds to the square inch, requiring very powerful engines for this purpose, as also to overcome the great friction created by the conveying the air-blast the distance traveled by it. In order to remedy these defects and to lessen the quantity of fuel, and also to increase the quantity and improve the quality of the iron produced, I construct the furnace as follows:

The furnace A is built of stone orbrick, substantiallyV in the usual form, the chamber B, in the'interior, being lined withfire-clay or brick C. A t the bottom of the furnace, and extending entirely around the lowestorcrucible part, b, thereof, and in height about equal to such part b, is an annular space or chamber, D, for receiving the air-blast,;and from which it is distributed to the lower part, b, of the furnace. Air is supplied to such annular chamber D by means of and throughjthepipe E and the connecting-passages e, andf.; l.Leading from such chamber D, and opening into the lower part or crucible b ofthefreducingfurnace, is a series of air-passages, -1 2 3, which extend inward from the air-chamber D, and open into the lower chamber, b, on every side thereof. The extent of the space between the air-chamber D and the furnace b, or the length of the air-passages l2 3, is gen-A erally about three feet, and is built of firebrick, which are most conveniently laid in two blocks or series of about equaly lengths and of tapering form, so as to meet and iit closely together; and through suclrbrick-work are madetthe air-passages 1 2 3which are generally about three-quartersY of an inclr in diameter at the outer and one-half an inch in diameter at their inner ends.

By thus supplying the fire-chamber on every side and on the top of and at different points `in the burning fuel withfjets of heated air, the

decarbouization of fthe fuel commences or is carried on from the'topandfroni the outside instead of from the bottom and center, as usual, and an intense heat isproduced, while the combustion is slower, and the combustion being most actively carried'on at the top and sides of the fuel the grate-bars remain comparatively cool, and are thereby made more durable.

The inside surface of the lire-clay ring D should be iiuted, as shown-inl Fig. 4, so as to prevent the fuel closely packing against the brick and interfering with proper distribution of the air.

The quantity of air admitted to the chamber E may be regulated and controlled by a sliding plate, F, by `which the mouths of the'tubes b may be more or less contracted and closed. Such lire-chamber E is wholly arched over with fire-brick, as shown in Fig. 2, in section, (a suitable opening, E', being made therein to allow the feeding the furnace,) through which arch numerous perforations, j', generally about *half an inch in diameter, are made to allow the carbonic oxides and products of combustion generated therein to pass into the outer or combustion chamber, H, which is also supplied with air from below through the spaces or openings g, which are between the iron plate C, the tire-brick D, and the air-tubes b, and in passing through which spaces the air becomes highly heated. A section of onel of such openings, g, is shown in Fig. 2.

The air'supplied to the combustion-chamber H becoming highly heated while passing thereto is rendered lighter than the carbonio 0X- ides continually entering from the fire-chamber E, and an intimate mixture or union of the air and gases takes place, utilizing the whole and producing their complete and perfect coinbustion.

The heating-power of the chambers E and H may be much increased and the combustion of the fuel rendered more complete by admitting into such chambers, through the tubes b and openings g, heated orsuper heated steam,

by means of a pipe, c, perforated or fitted with jet-pipes under such tubes and openin gs.

Rising above or in continuation, substantially, of the plate C are two walls, h 7L', made of fire-clay rings, one forming the outer wall of the furnace and the other placed within it, a space of three or four inches being between the two, such walls extending upward toward and nearly to the top of the furnace.

The object and purpose of this construction are to prevent radiation of the heat, and thereby secure more intense heat in the combustion-chamber and the annealing or heating chambers above it; and as a result of such construction I am enabled to preserve both a greater and a more uniform heat.

Above the combustion-chamber H, and being, in fact, an extension or continuation of it, is the heating or annealing chamber J, which is divided into separate compartments by open platforms k, through which the heated air can freely pass, the several compartments having separate doors K, so that ingots can be placed in or taken out of any compartment at pleasure. All the ingots being treated can thus be kept separate from each other, and the heat from the combustion-chamber will readily and certainly act upon every part of such ingots.

By admitting stealn from the pipe cinto the same tubes or passages which supply air to both the fire and combustion chambers, an increased draft upward is created in such tubes or passages, and, consequently, larger quantities of air are carried to such chambers, and a greater intensity of heat is obtained from a given amount of coal. The same construction of furnace is also well adapted for and can be used for annealing iron or glass.

What I claim as my invention, and desire to secure by Letters Patent, isv l. A furnace for heating or annealing steel, glass, Sac., having its heat generator constructed in two chambers, substantially as described, and so arranged that heated currents of air, or air and steam, will be supplied to both such chambers, and the inner chamber being separated from the outer by a perforated v arch or top, the entire furnace being constructed and operating substantially as and for the purposes set forth.

2. The arrangement of the several separate annealing-chambers, substantially as and for the purposes set forth.

S. D. LAw, FRED. B. SEARs. 

